Method and system for photoselective vaporization for gynecological treatments

ABSTRACT

A method for photoselective vaporization of uterine tissue includes delivering laser radiation to the treatment area on the tissue, via an optical fiber for example, wherein the laser radiation has a wavelength and irradiance in the treatment area on the surface of the tissue sufficient because vaporization of a substantially greater volume of tissue than a volume of residual coagulated tissue caused by the laser radiation. The laser radiation is generated using a neodymium doped solid-state laser, including optics producing a second or higher harmonic output with greater than 60 watts average output power. The delivered laser radiation has a wavelength for example in a range of about 200 nm to about 650 nm, and has an average irradiance in the treatment area greater than about 10 kilowatts/cm 2 , in a spot size of at least 0.05 mm 2 .

RELATED APPLICATION INFORMATION

This application is a divisional application of U.S. patent applicationSer. No. 10/371,080 filed 21 Feb. 2003.

Application Ser. No. 10/371,080 claims the benefit of U.S. ProvisionalApplication No. 60/358,356, entitled METHOD FOR TREATMENT OFGYNECOLOGICAL CONDITIONS USING A HIGH POWER LASER IN CONJUCTION WITH AHYSTEROSCOPE, filed 22 Feb. 2002.

The present application is related to, and incorporates by reference asif fully set forth herein, U.S. patent application Ser. No. 10/278,723,entitled METHOD AND SYSTEM FOR PHOTOSELECTIVE VAPORIZATION OF THEPROSTATE, AND OTHER TISSUE, filed 23 Oct. 2002; U.S. patent applicationSer. No. 09/737,721, entitled METHODS FOR LASER TREATMENT OF SOFTTISSUE, filed 15 Dec. 2000 (now U.S. Pat. No. 6,554,824); and U.S.patent application Ser. No. 10/279,087, entitled METHOD AND SYSTEM FORTREATMENT OF BENIGN PROSTATIC HYPERTROPHY (BPH), invented by Murray, etal.; filed: 23 Oct. 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to laser treatment of tissue,and more particularly to photoselective vaporization of tissue,including uterine tissue, as applied to the treatment of gynecologicalconditions.

2. Description of Related Art

A commonly employed procedure for removal of tissue in the treatment ofgynecological conditions involves the use of a hysteroscope and a smallwire loop energized by radio frequency energy to cut tissue.

Nd:YAG lasers delivering output with a wavelength of 1064 nm have beenused for the treatment of gynecological conditions such as the ablationof the endometrium. Although 1064 nm light is hemostatic at high powerlevels, its low absorption in blood and uterine tissue leads toinefficient ablation and a large residual layer of thermally denaturedtissue several millimeters thick.

High power densities are required for rapid and efficient vaporizationof tissue. The difficulty of achieving higher average output powerdensities is that when high input powers are supplied to the laserelement from an excitation source such as an arclamp a large amount ofheat is generated in the lasing element. This heat induces variousdeleterious effects in the lasing element. In particular the temperaturedifference between the coolant and the hot lasing element generates athermally induced graded index lens that decreases the beam quality ofthe laser and causes the laser to operate with more transverse opticalmodes than it would otherwise.

The M² parameter is a well established convention for defining the beamquality of a laser and is discussed in pages 480-482 of Orazio Sveltoand David C. Hanna, Principles of Lasers, Plenum Press, New York, 1998,which is incorporated herein by reference. The beam quality measures thedegree to which the intensity distribution is Guassian. The quantity M²is sometimes called inverse beam quality rather than beam quality but inthis application it will be referred to as beam quality. M² is definedas${{M_{x}^{2} \equiv \frac{( {\sigma_{x}\sigma_{f}} )_{NG}}{( {\sigma_{x}\sigma_{f}} )_{G}}} = {4{\pi( {\sigma_{x}\sigma_{f}} )}_{NG}}},$

-   -   where π refers to the number 3.14 . . . , σ is used to represent        the spot size, the subscripts x and f represent the spatial and        frequency domains along the x-axis, respectively, and the        subscripts G and NG signify Guassian and non-Guassian,        respectively. The x-axis is transverse to the direction of        propagation of the beam. The beam quality in any direction        transverse to the beam may be essentially the same. Therefore        the subscript x is dropped from the M² elsewhere in the        specification. The beam widths or σs are determined based on the        standard deviation of the position, where the squared deviation        of each position is weighted by the intensity at that point. The        beam width in the frequency domain σ_(f) is the beam width of        the beam after being Fourier transformed.

The formula usually used for calculating the angular divergence, θ, of abeam of light of wavelength λ is strictly valid only for a beam having aGuassian intensity distribution. The concept of beam quality facilitatesthe derivation of the angular divergence, θ, for the beam with anon-Guassian intensity distribution, according to$\theta = {{M^{2}( \frac{2\lambda}{\pi\quad\sigma_{x}} )}.}$

For example, a TEM00 laser beam has a high beam quality with an M² of 1,whereas by comparison, high power surgical lasers operate with M² valuesgreater than 100.

The Applicants have recognized that high power lasers typically have anM²>144. The larger number of modes makes M² larger and makes itdifficult to focus the light into small, low numerical aperture fibersand reduces the ability to project high power density light onto tissue.As a result, the vaporization efficiency of CW arclamp pumped 532 nmlasers is significantly reduced.

Surgical procedures within the uterus have unique risks. For example,precision surgery is of high importance for patients who want tomaintain their fertility. Any surgery in the uterus must avoid weakeningof the wall of the uterus, which could lead to complications duringpregnancy. Also, the physiological diversity of the uterus increases thedifficulty of intrauterine operations. The cornual areas of the uterusrepresent a vulnerable portion of the uterus. In case of a myoma in thecornu, the uterine wall is further thinned by the myoma, which increasesthe risk of intraoperative perforation of the uterine wall. Even ifperforation does not occur, the presence of a thin uterine wall couldpredispose the patient to bowel injury. As stated by Indman, J.Reproduct. Med. 1991, lack of precise knowledge of the minimum thicknessof the uterine wall may be the limiting factor in determining the safetyof use of the 1064 nm Nd:YAG laser for endometrial ablation.

SUMMARY OF THE INVENTION

Photoselective vaporization of tissue, such as tissue subject of removalfor treatment of gynecological conditions, is based upon applying a highintensity radiation to tissue using a radiation that is highlyabsorptive in the tissue, while being absorbed only to a negligibledegree by water or other irrigant during the operation, at powerdensities such that the majority of the energy is converted tovaporization of the tissue without significant residual coagulation ofadjacent tissue.

The present invention provides a method for treating gynecologicconditions, including conditions involving uterine tissue, such asintramural and intracavitery uterine myomas, leiomyoma uteri,rhabdomyoma, endometriosis, endometrial hyperplasia, endometrial cysts,endometrial polyps, menorrhagia, uterine septa, intrauterine adhesions,or cervical intraepithelial neoplasia. Other gynecological conditionsinvolving the female reproductive organs such as the fallopian tubes,the ovaries, and the vagina, are also treatable according to the presentinvention. Treatment according to the embodiments of present inventionis executed by vaporizing, incising, or coagulating tissue, such asuterine tissue, using a laser that generates light with an average powergreater than 40 watts and a wavelength between 300 and 700 nm where theoutput beam of the laser is delivered to the target tissue through anoptical waveguide, such as an optical fiber that emits light in forwarddirection (end-firing) or in a laterally directed manner (side-firing)where laterally means at an angle of 10°-170° with respect to the fiberaxis, and where the waveguide is guided into the vagina or the uterinecavity using a hysteroscope. In embodiments of the invention, thehysteroscope is equipped with a rigid tip. In other embodiments of theinvention, the hysteroscope is equipped with a flexible tip, which canbe manipulated by the surgeon, allowing greater control over theprocedure, and access to more regions of the target tissue.

In other embodiments, the wavelength of the delivered radiation isbetween 1100 and 1800 nm, or in other bands that are efficientlyabsorbed by the target tissue.

Yet other embodiments employ a laser system, that generates light of twowavelengths, with for example two lasers arranged to provide light to abeam delivery system, with the light of the first wavelength having anaverage power greater than 40 watts, and in some embodiments more than60 Watts, and a wavelength between 300 and 700 nm, such as a wavelengthof 532 nm, and the light of the second wavelength having a wavelength of1064 nm. In alternative one or two wavelength systems, delivered lightis between 1100 and 1800 nm.

According to one embodiment of the invention, a method for treatinggynecological conditions comprises the steps of providing a solid-statelaser having a laser element positioned to receive pump radiation froman excitation source; in some cases modulating the source to cause thelaser to emit pulsed laser light; and delivering the laser light totargeted tissue. Various solid-state lasers may be used for thispurpose, including (without limitation), a Q-switched laser using afrequency doubling crystal such as potassium-titanyl-phosphate (KTP),pumped using a diode array, an arc lamp or a flash lamp. WhileQ-switching induces short, “micro-pulses,” a “macro-pulse” duration ofthe laser light is preferably in the range of 0.1 to 500 milliseconds,induced by for example modulating the pump energy with the desiredmacro-pulse length. The wavelength of the laser light is preferablybetween 200 and 1000 nm, and more preferably between about 300 and 700nm. The laser light is preferably delivered to the targeted tissuethrough an optical fiber terminating at or near a distal end in aside-firing or end-firing probe.

Operation of the solid-state laser in a “macro-pulsed” mode is moreefficient in vaporizing tissue than a CW laser of the same averagepower. This is in part because the heat generated in a superficialtissue layer, which depth is defined by the optical penetration depth ofthe laser beam, doesn't have time to significantly diffuse into deepertissue layers during each macro pulse. The heat stays confined in thesuperficial tissue layer and leads to a rapid heating of the tissue tothe boiling point of water. The thermal energy generated within a tissuevolume has to exceed the vaporization enthalpy of water to fullyvaporize the tissue. For a laser operated in a macro-pulsed mode thiscondition is met for a larger tissue volume than for a laser operated ina continuous mode. The macro-pulsed laser is also more efficient and hashigher beam quality, with M2 values typically less than 144, than acontinuous wave laser with same average output power. The higher beamquality allows for higher irradiances on the tissue and thus a morerapid tissue vaporization.

According to a second embodiment of the invention, a method for treatinguterine tissue comprises the steps of providing a solid-state laserhaving a laser element positioned to receive pump radiation from a pumpradiation source; modulating the pump radiation source to cause thelaser element to emit laser light having a pulse duration of between 0.1milliseconds and 500 milliseconds and an average output power exceeding20 watts; and delivering the laser light to targeted tissue.

According to a third embodiment of the invention, a method for treatinggynecological conditions comprises the steps of providing a solid-statelaser having a laser element positioned to receive pump radiation from apump radiation source; Q-switching the laser to generate aquasi-continuous wave (CW) beam having an average output power exceeding60 watts; and, delivering the beam to targeted tissue.

According to a fourth embodiment of the invention, a method for treatinggynecological conditions comprises the steps of providing a solid-statelaser having a laser element positioned to receive pump radiation from apump radiation source such as a laser diode; Q-switching the laser togenerate a quasi-continuous wave (CW) beam having an average outputpower exceeding 20 watts with an M² less than 144; and delivering thebeam to uterine tissue.

It has been recognized that as more and more laser energy is consumed byvaporization of the tissue, the amount of laser energy leading toresidual tissue coagulation gets smaller, i.e. the amount of residualcoagulation drops, and the side effects attendant to the residual injurycaused by the surgery drop dramatically. Thus, the extent of the zone ofthermal damage characterized by tissue coagulation left after theprocedure gets smaller with increasing volumetric power density, whilethe rate of vaporization increases. Substantial and surprisingimprovement in results is achieved. It has been recognized thatincreasing the volumetric power density absorbed in the tissue to beablated, has the result of decreasing the extent of residual injury ofthe surrounding tissue. This recognition leads to the use of higherpower laser systems, with greater levels of irradiance at the treatmentarea on the tissue, while achieving the lower levels of adverse sideeffects and a quicker operation times.

Although the invention can be generalized other types of tissue, oneembodiment of the invention provides a method for photoselectivevaporization of uterine tissue, including for example the endometriumand myomas in the uterine wall. According to this embodiment, the methodincludes delivering laser radiation to the treatment area on the tissue,via an optical fiber for example, wherein the laser radiation has awavelength and irradiance in the treatment area on the surface of thetissue sufficient because vaporization of a substantially greater volumeof tissue than a volume of residual coagulated tissue caused by thelaser radiation. In one embodiment, the laser radiation is generatedusing a neodymium doped solid-state laser, including optics producing asecond or higher harmonic output with greater than 60 watts averageoutput power, and for example 80 watts average output power, or more.The laser radiation is coupled into an optical fiber adapted to directlaser radiation from the fiber to the treatment area on the surface ofthe tissue. For the treatment within the uterus, the fiber optic isinserted via hysteroscope, including lumens for delivering irrigants tothe treatment area, and for direct visualization during the treatment.For treatment in the uterine cornua, or other difficult to reachregions, and more generally because of physiological diversity in theuterus, a flexible tip hysteroscope is used in embodiments of thepresent invention.

In other embodiments, the delivered laser radiation has a wavelength ina range of about 300 nm to about 700 nm, and has an average irradiancein the treatment area greater than about 10 kilowatts/cm², in a spotsize of at least 0.05 mm². More preferably, the irradiance is greaterthan about 20 kilowatts/cm², and even more preferably greater than about30 kilowatts/cm². The spot size in preferred systems is for example lessthan about 0.8 mm².

Accordingly, in one embodiment, the second harmonic output of theneodymium dope solid-state laser is applied using an optical fiber witha flat tip for emitting radiation from the end, or with a side-firingtip. When using a side-firing tip, which causes a diverging beam to bedirected out of the optical fiber, the time is placed close to thetissue, within about 1 mm from the side of the side-firing tip tocontacting the side of the tip. Close placement increases the irradiancedelivered to the treatment area so that higher irradiance is availablewith solid-state lasers generating a 60 to 80 watts average outputpower.

According to the present invention, the efficiency of the vaporizationand the reduction of injury to residual tissue are sufficient that theprocedure may be carried out while applying less anesthesia during thedelivery of laser energy, and throughout the procedure, than duringother procedures. Anesthesia options for a procedure according to thepresent invention include, but are not limited to, paracervical block,and general or regional anesthesia techniques.

Furthermore, embodiments of the invention include the delivery of thelaser energy using a Q-switched, solid-state laser which producesmicro-pulses in combination with applying pump power to the laser mediumin a sequence a pulses so that output radiation is produced inmacro-pulses having a peak power of greater than 200 watts, and morepreferably about 240 watts or greater. The peak irradiance in thetreatment area during the pulses is thereby substantially increased, andpreferably greater than 50 kilowatts/cm², and as much as 90kilowatts/cm² in some embodiments of the invention.

Other aspects and advantages of the present invention can be seen onreview the figures, the detailed description, and the claims whichfollow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a laser system for implementing the tissue ablationmethods of the invention;

FIG. 2 depicts a side-firing probe for use with the system of FIG. 1;

FIG. 3 depicts an exemplary output waveform of the FIG. 1 laser when thelaser is operated in a macro-pulsed mode; and

FIG. 4 depicts an exemplary output waveform of the FIG. 1 laser when thelaser is operated in a quasi-CW mode.

FIG. 5 is a block diagram of a laser system adaptable for use accordingto the present invention.

FIG. 6 is a block diagram of an alternative laser system adaptable foruse according to the present invention.

FIG. 7 is a diagram of a flexible tip hysteroscope, adaptable for useaccording to the present invention.

FIG. 8 illustrates absorption depth in tissue for 532 nm light.

FIG. 9 illustrates absorption depth in tissue for 1064 nm light.

FIG. 10 is a diagram of a beam path from an end view of a side firingtip, according to one embodiment of the present invention.

FIG. 11 is a diagram of a beam path from a side view of the side firingtip of FIG. 10, according to one embodiment of the present invention.

FIG. 12 is a heuristic diagram illustrating operation of the presentinvention.

FIG. 13 illustrates representative gynecological conditions treatableaccording to the present invention.

FIG. 14 illustrates application of a side-firing probe on a hysteroscopefor ablation of tissue in treatment of a protruding, intracaviteryuterine myoma within the right uterine cornu.

FIG. 15 illustrates application of an end-firing probe on a flexible tiphysteroscope for ablation of tissue in treatment of a protruding,intracavitery uterine myoma.

DETAILED DESCRIPTION

FIG. 1 is a block diagram depicting an exemplary laser system 100 whichmay be employed for implementing the present invention. Laser system 100includes a solid-state laser 102, which is used to generate laser lightfor delivery through optical fiber 106 to target tissue 104. As will bediscussed in further detail herein below, laser 102 is capable of beingoperated in a “macro-pulsed” mode, wherein the laser light is emitted asmacro-pulses having relatively long pulse durations.

Laser 102 more specifically comprises a laser element assembly 110, pumpsource 112, and frequency doubling crystal 122. In the preferredembodiment, laser element 110 outputs 1064 nm light which is focusedinto frequency doubling crystal 122 to create 532 nm light. According toone implementation, laser element assembly 110 may be neodymium dopedYAG (Nd:YAG) crystal, which emits light having a wavelength of 1064 nm(infrared light) when excited by pump source 112. Laser element 110 mayalternatively be fabricated from any suitable material whereintransition and lanthanide metal ions are disposed within a crystallinehost (such as YAG, Lithium Yttrium Fluoride, Sapphire, Alexandrite,Spinel, Yttrium Orthoaluminate, Potassium Gadolinium Tungstate, YttriumOrthovandate, or Lanthanum Scandium Borate). Laser element 110 ispositioned proximal to pump source 112 and may be arranged in parallelrelation therewith, although other geometries and configurations may beemployed.

Pump source 112 may be any device or apparatus operable to excite laserelement assembly 110. Non-limiting examples of devices which may be usedas pump source 112, include: arc lamps, flashlamps, and laser diodes.

A Q-switch 114 disposed within laser 102 may be operated in a repetitivemode to cause a train of micro-pulses to be generated by laser 102.Typically the micro-pulses are less than 1 microsecond in durationseparated by about 40 microseconds, creating a quasi-continuous wavetrain. Q-switch 114 is preferably of the acousto-optic type, but mayalternatively comprise a mechanical device such as a rotating prism oraperture, an electro-optical device, or a saturable absorber.

Laser 102 is provided with a control system 116 for controlling andoperating laser 102. Control system 116 will typically include a controlprocessor which receives input from user controls (including but notlimited to a beam on/off control, a beam power control, and a pulseduration control) and processes the input to accordingly generate outputsignals for adjusting characteristics of the output beam to match theuser inputted values or conditions. With respect to pulse durationadjustment, control system 116 applies an output signal to a powersupply (not shown) driving pump source 112 which modulates the energysupplied thereto, in turn controlling the pulse duration of the outputbeam.

Although FIG. 1 shows a frequency doubled laser with an intracavityfrequency doubling element, it is only by way of example. The infraredlight can be internally or externally frequency doubled using non-linearcrystals such as KTP, Lithium Triborate (LBO), or Beta Barium Borate(BBO) to produce second harmonic 532 nm green light, and higherharmonics. The frequency doubled, 532 nm wavelength and the shorterwavelength higher harmonic beams are better absorbed by the tissue, andpromote more efficient tissue ablation.

In one preferred embodiment the resonant cavity control system is thatdescribed in U.S. Pat. No. 5,151,909, which is incorporated by referenceas if fully set forth herein.

Laser 102 further includes an output port couplable to optical fiber106. Output port 118 directs the light generated by laser 102 intooptical fiber 106 for delivery to tissue 104. Mirrors 124, 126, 128, and130 direct light from the lasing element 110 to the frequency doublingcrystal 122, in addition to forming the resonant cavity of the laser.Mirrors 124, 126, 128, and 130 are configured for focusing the light toform an image just in front of the frequency doubling crystal 122 on theside closer to mirror 130, and to compensate for thermal lensing in thelasing element. Although mirrors 124, 126, 128, and 130 are illustratedas flat and parallel to the walls of the laser, typically the focusingis achieved by curving and/or angling the mirrors. Alternativelytransmissive optical elements could be used to focus the light andcompensate for the thermal imaging. Mirrors 124, 128 and 130 reflectboth the wavelength of light produced by the lasing element (e.g. 1064nm) and the wavelength of the frequency doubled light (e.g. 532 nm).Mirror 126 only reflects the light originating from the lasing element110 (e.g. 1064 nm) but is transparent to the frequency doubled light(e.g. 532 nm), forming an output window. Higher harmonic outputs mayalso be generated from the 1064 nm line, or other line amplified in thelaser, including third and fourth harmonics, for shorter wavelengths.Other laser systems may be used, including but not limited to Sapphirelasers, diode lasers, and dye lasers, which are adapted to provide theoutput power and wavelengths described herein, including wavelengths inthe ranges from 200 nm to 1000 nm and from 1100 nm to 1800 nm, forexample.

While a bare fiber may be utilized for certain procedures, optical fiber106 preferably terminates in a tip 140 having optical elements, orotherwise adapted, for shaping and/or orienting the beam emitted byoptical fiber 106 so as to optimize the tissue ablation process.

FIG. 2 depicts a side-firing probe tip 200, which may be used as tip 140(FIG. 1). The tip 140 is treated to deflect light sideways. Someexamples of methods for deflecting the light sideways are to include alight scattering material in the tip 140 and/or to place a reflectiveelement in the tip 140. The reflective element could be angled at 45°,for example; to deflect the light at 90° with respect to the axis of thefiber 106. Side-firing probe tip 200 includes an optically transparentsleeve 202 having a transparent window 204 (which may be constructed asa cutout in the wall of sleeve 202 through which the beam is emitted ina direction transverse to the optical axis of fiber 106.) An acceptablerange of angles in which to deflect the light beam is between about 40to 120 degrees with respect to the axis of the fiber. The preferredembodiments use an angle of either 70 or 100. The angle of 80° ispreferred from the standpoint of the ease in manufacturing the tip 200and the angle of 90° is preferred from the standpoint of the ease inaiming the side firing light.

In a typical mode of operation, optical fiber 106 is held within anendoscope such as a hysteroscope or similar instrument that allows theclinician to precisely position the distal end of the optical fiberadjacent to the targeted tissue. The endoscope also has channels forsupplying and removing an irrigant solution to and from the tissue. Inaddition, light and image guides are also included for illuminating andimaging the tissue so that the clinician may direct the laser light andassess the progress and efficacy of the ablation procedure. Physiologicsaline solution, typically containing 0.9% sodium chloride, is used asthe irrigant in gynecological procedures according to the presentinvention.

FIG. 3 illustrates an exemplary output waveform applied to tissue 104when laser 102 is operated in the macro-pulsed mode. Each macro-pulse302 is defined by a train of Q-switched micro-pulses 304. While arelatively small number of micro-pulses 302 are depicted for purposes ofclarity, an actual macro-pulse may comprise hundreds or thousands ofcomponent micro-pulses 304. In the preferred embodiment there arebetween 2 and 12,200 micro-pulses per macro-pulse.

An arc lamp, for example, when used as the pump source 112, is kept at alow power level between pulses that are preferably just enough tomaintain the arc. These low pump powers are below the lasing thresholdof the laser; as a consequence, there is no laser output betweenmacro-pulses.

As mentioned above, the pulse duration or width D (FIG. 3) of the outputbeam is governed by the modulation of pump source 112, and morespecifically by the period during which the pump source 112 ismaintained in an “on” or high-power condition. In other words, thelonger the pump source 112 is maintained in an on condition, the longerthe pulse width. Typically, laser 102 will be capable of deliveringpulses 302 having pulse durations D in the range of 1 to 20 milliseconds(2 to 490 micro-pulses) or 1 to 50 milliseconds (2 to 1,220micro-pulses) and average output powers preferably exceeding 60 wattsand preferably up to 100 or 200 watts. The ratio of D to the period ofthe macro-pulses defines the duty cycle, which is typically between 10and 50%.

In accordance with one embodiment of the invention, a laser system 100of the foregoing description is employed to treat gynecologicalconditions by ablating targeted tissue 104. The clinician may utilize anendoscope or similar instrument to guide the distal end and tip 140 ofoptical fiber 106 into alignment with the targeted tissue 104. Lasersystem 100 is then operated in the macro-pulsed mode so that laser 102generates laser light having the pulsed waveform depicted in FIG. 3 anddelivers it through optical fiber 106 to tissue 104.

Prior art techniques for treatment of gynecological conditions by laserablation (such as the technique described by Indman. in “High-PowerNd:YAG Laser Ablation of the Endometrium,” Journal of ReproductiveMedicine, Vol. 36, No. 7, July 1991)) utilized an Nd:YAG laser toirradiate the uterine tissue. Although such lasers do produce moderatelyhigh average powers, they have a large number of transverse modes and assuch, produce highly divergent light when focused into smallfiberoptics. Further, the 1064 nm wavelength is less efficientlyabsorbed in the target tissue, that the wavelengths desirable accordingto the present invention. These characteristics of prior art 1064 nmsystems lead to less than optimal power densities when the laser lightis directed at tissue. As a consequence, ablation rates are relativelyslow, significantly lengthening procedure times. Further, undesirablethermal damage to deeper tissue layers may occur. In contrast, it hasbeen found that a macro-pulsed beam, such as that generated by laser102, helps to accelerate ablation rates and reducing procedure time.

The macropulsing can also increase efficiency because the thresholdvoltage required for lasing while macropulsing (the operating threshold)is lower than the initial threshold voltage for lasing (cold threshold).

Macropulsing is also more efficient for producing green light becausethe conversion of infrared light to frequency doubled light increases asthe square of the infrared light intensity. The higher peak powers ofthe macro-pulsed infrared light leads to higher second harmonicconversion efficiency. For example, at any given time, the input powerand output power of a frequency-doubled laser using KTP are relatedaccording toPo=A(Pi)^(2,)

Where A is an experimentally determined positive constant. This equationrelates the peak input power to the peak output power. However, theaverage input power and output power for a duty cycle of k percent aregiven by<Pi>=k(Pi) and<Po>=k(Po)=kA(Pi)² =A(<Pi>)² /k,where the brackets “< >” indicate an average value of the enclosedquantity. Thus, decreasing the duty cycle from 100% to 50% (i.e.reducing k from 1 to 0.5) while simultaneously doubling the peak inputpower Pi results in no change to the average input power <Pi> and adoubling of the average output power <Po>. Pulse modulating ormacropulsing using Q-switching, for example, enables reaching higheraverage output powers with less thermal lensing due to the lower inputpower.

Additionally, it is possible that the frequency doubling crystal hasnonlinearly increasing output power as a function of the input power. Inother words the second derivative of the output power with respect tothe input power may be positive, in which case the rate of increase ofthe output power increases with increasing input power. Specifically, insuch a case the functional dependence of the instantaneous or peakoutput power, Po, on the instantaneous or peak input power, Pi, is suchthatd ²(Po)/d(Pi)²>0.When this is true, and Po is an increasing function of Pi, the higherpeak input power results in a more efficient laser because ratio of theoutput to input power increases.

Pump source modulation of the laser can produce high peak powermacro-pulses and affect the efficiency of the average power output.Macro-pulse in excess of a steady state power can substantially improvethe initiation of the vaporization of tissue. The higher peak power ofthe macro-pulse rapidly may initiate charring which in turn serves as anadditional chromophore for the incident energy and enhances thevaporization rate. A 30% macro-pulse duty cycle is sufficient toincrease the average power output of an arc lamp pumped laser to greaterthan 80 watts. Additionally the pump modulation generates macro-pulsewith pulse powers greater than 240 watts.

By way of a non-limiting example, tissue 104 may be efficiently andrapidly ablated when laser 102 is operated at an output power of 80 to100 watts, a pulse duration of 1-50 milliseconds, and a wavelength of532 nm.

In accordance with a second method embodiment of the invention, lasersystem 100 may be utilized to ablate other types of tissue 104 involvedin gynecological conditions. The clinician may utilize an endoscope orsimilar instrument to guide the distal end and tip 140 of optical fiber106 into alignment with the tissue 104. Laser system 100 is thenoperated in the macro-pulsed mode so that laser light having the pulsedwaveform depicted in FIG. 3 is generated by laser 102 and deliveredthrough optical fiber 106 to tissue 104. To achieve adequate results,laser system 100 is adjusted to emit a beam having a pulse durationbetween 0.1 and 500 milliseconds, and an output power of at least 20watts. Upon vaporization of the required volume of tissue 104, (whichmay be assessed via an imaging channel contained in the endoscope), theoutput beam of laser 102 is turned off.

In a third method embodiment of the invention, treatment ofgynecological conditions is effected by operating laser 102 in aquasi-CW mode at an output power greater than 60 watts. The increaseddenaturization of the tissue is dramatic with increases in power,suggesting a threshold effect. As depicted in FIG. 4, laser 102generates a continuous train of Q-switched micro-pulses 400 whenoperated in quasi-CW mode. The laser light is then delivered via opticalfiber 106 to targeted tissue 104. Operation in a quasi-CW mode at powersabove 60 watts facilitates formation of char and consequent rapidablation rates, whereas operation in a quasi-CW mode at powers below 60watts forms char more slowly and causes more thermal damage to underlingtissue.

A fourth embodiment of this invention is to produce a high power, highbeam quality laser that can project high power density laser light ontotissue. To do this the number of transverse optical modes supported bythe resonator needs to be kept as low as possible.

Small M² and high average powers can be achieved by reducing the degreeof thermal lensing in the laser element. Using laser diodes as theexcitation source is one effective way of greatly reducing both the sizeof the lasing element and the thermal gradient responsible for creatingthe thermal lens. The reason for this is that while 2-10% of the lightproduced from a flashlamp or arc lamp is converted into useful laserlight 30-60% of the light emitted from laser diodes can be converted tolaser light. Since the energy that is not converted to laser light isconverted into heat, laser diodes deposit significantly less heat in thelasing element and as a consequence create a less powerful thermal lens.In this manner laser diodes can be used to pump crystalline laserelements or fiber lasers to produce high beam quality lasers. Slab andwaveguide lasers that can be pumped by laser diodes, arc lamps, orflashlamps are another method of creating low M² lasers. This is becausethe thermal gradient produced in slab lasers is linear across the thindimension of the slab and not radially dependent in contrast to atypical cylindrical lasing element. The linear thermal gradient does notproduce a thermal lens resulting in low M² values.

For example, as a result of the low M² some embodiments of thisinvention are capable producing laser light that upon exiting a flat endof a fiber having a diameter of 600 μm has a divergence of 15.3° orlower; 15° or lower; 10° or lower; or 5° or lower, and the power densitycan be 13,400 watts per cm², or greater.

FIG. 5 shows a block diagram of a preferred laser system according tothe present invention. In FIG. 5, a laser resonator is defined by endmirror 10, turning mirrors 12 and 14, and end mirror 16. All of thesemirrors are high reflecting (greater than 99.8%) at the 1064 nm line. Anoptical path 24 is defined by these mirrors. A gain medium 18 comprisinga Nd:YAG rod is mounted along the optical path within a pump housing 29.A laser diode array 28D is also mounted within the housing and suppliespump power to the gain medium in response to current generated in powersupply 30. Representative laser diodes include laser diodes providingoutput in the range of 805 to 820 nm in wavelength with an input powerto the array of pumping diodes in the range of 300 to 500 Watts. Thelaser diodes used for pump energy are operated in a modulatedmacro-pulse mode, or in a continuous mode, as suits a particularimplementation.

Also in the optical path 24 is a Q-switch 20 between the lamp housing 29and the turning mirror 12. A non-linear crystal 22 is mounted betweenthe turning mirror 14 and the back mirror 16. This non-linear crystal ispreferably a KTP crystal aligned for frequency doubling to generate a532 nm beam. Mirrors 16 and 14 are highly reflective at 532 nm, whilemirror 12 is transmissive and operates as an output coupler for the 532nm beam.

Thus, the laser resonator is designed for resonating at a firstfrequency, i.e., 1064 nm along the Z-shaped optical path 24. A secondfrequency derived from the 1064 nm beam is generated in the KTP crystal22. This beam travels along the path 26 a and is extracted from theresonator to supply an output beam along path 26 b.

The output beam along path 26 b passes through a controllable attenuator36, a beam splitter 38, which supplies a portion of the output beam to asurgical detector 40, and a component group 42 as described in moredetail below. The attenuator, detector, and component group are allcoupled to a data processing system 34, across lines 34 j, 34 k, and 34p.

The Q-switch 20 is controlled by Q-switch driver 21, which is, in turn,coupled to data processor 34 across line 34 i. In the preferred system,the Q-switch is an acoustic-optic Q-switch.

Similarly, the power supply 30 generates an electrical power signal forcontrolling the diode array 28D. This power signal is controlled by thedata processor 34 across line 34 h and by drive circuitry 32 across line32 a. Drive circuitry 32 a is controlled by the data processor acrosslines 34 a through 34 g. A sensor 57 is coupled with the data processorto sense an environmental condition, such as temperature or humidity,that affects operation of the laser system. A modem 56 is connected tothe data processor 34, providing an interface for remote access tomemory in the data processor. Finally, a control panel 35, by which auser can supply input signals and parameters, is provided. This controlpanel 35 is connected to the data processor 34 across line 34 n.

In alternative systems, the non-linear crystal may be mounted outsidethe resonant cavity of the resonator. Also, it may be used forextracting outputs other than the second harmonic, such assum-of-frequency derivation or the like.

The wavelength used according to the present invention for gynecologicalconditions treatment should be strongly absorbed in the tissue to helpinitiate and maintain tissue vaporization without creating deep tissueheating. The wavelength also must be minimally absorbed by the irrigantused during the procedure, typically physiologic saline solution. The532 nm light produced by the system of FIG. 5, is both strongly absorbedin oxyhemoglobin and weakly absorbed in physiologic saline solution.Oxyhemoglobin is readily present in uterine tissue and serves as anefficient chromophore for 532 nm light. The differential in absorptioncoefficients between oxyhemoglobin and water at 532 nm is approximately5 orders of magnitude (10⁵). In other embodiments, wavelengths in therange from 200 nm-650 nm are used, which have strong oxyhemoglobinabsorption and relatively weak water absorption (>10²×). In yet otherembodiments, wavelengths in the range from 200 nm to 650 nm range areused, which have strong oxyhemoglobin absorption and relatively weakwater absorption (>10×).

Of course, as shown in FIG. 6, in which like components have the samereference numerals as in FIG. 5, alternative pump power sources, such asarc lamps 28, and flash lamps, other lasers for longitudinal pumping,and others, can be used as suits the needs of a particular gain mediumand application of the laser system.

The laser systems shown in FIGS. 5 and 6 can be modified by removingboth the Q-switch and the external surgical attenuator. The Q-switch andsurgical attenuator are removed because the modulated pump powerprovides a great deal of flexibility in controlling the output power ofthe laser not attainable using a Q-switch. The data processing systemcan be programmed to maintain a constant thermal load in the lasersystem while varying the peak pump power widely. Thus, the peak currentand duty cycle of the pump power source can be adjusted in such a way tokeep the average pump power constant, but the second harmonic powerduring the ready and work modes adjusted by selecting the peak currentand duty cycle. Although it may be necessary to use attenuators in thebeamline during the ready mode in order to extract an aim beam, suchattenuators may well be eliminated for the work mode. The average powerdoes not have to be constant, rather it can be maintained at levelswhich keep thermal focusing of the gain medium within the range ofstability of the resonator.

A representative laser system adapted for delivery of energy asdescribed above, comprises an 80 watt average power, 532 nm outputwavelength, solid state, intra-cavity frequency doubled Nd:YAG laser. Toobtain optimal efficiency, an arc lamp pump source is modulated at aperiod of 4.5 ms with a 16 ms duty cycle, generating 285 watts peakmacro-pulse power. An intra-cavity acousto-optic AO Q-switch is used tofurther modulate the energy at a period of 40 kHz with a 450 usmicro-pulse. The laser energy is coupled to a side firing fiber opticdelivery device for delivery to uterine tissue.

The laser system uses a combination touch screen and control knob userinterface to assist the operator in setting up the surgical parameters,including power levels and pulse sequence specifications. The averagepower setting is prominently displayed on the screen. Parameteradjustments are made by first activating (touching) the desiredparameter box on the screen and then turning the knob. The laser systemuses a secure card key interface to enable the laser. The system istransportable. The system offers convenient storage and a fiber deliverydevice pole.

An example of an endoscope, in particular a hysteroscope, for use withthe present invention is shown in FIG. 7. The hysteroscope has a distalend 200 and a proximal end 201. Laser radiation 205 is directed from andend firing fiber through an opening 206, by a fiber optic component.Water, Ringer Lactate or saline solution is delivered and removed fromthe treatment area via lumens in the probe. A viewing optic is alsoplaced in the opening 206, by which the surgeon is able to view thetreatment area during the procedure. On the proximal end 201 of theendoscope, an irrigation port 203 for flow of the irrigant is provided.Also, a fiber port 207 is used for insertion and removal of the fiberoptic delivering laser radiation to the treatment area. A light sourceconnector 209 is used for supplying light to the treatment area forvisualization. An viewing port 211, which can be coupled to a videocamera, or looked into directly, is also included on the representativehysteroscope. The endoscope includes a flexible tip in one embodiment,and controls (not shown) in the near proximal end 201, by which thesurgeon deflects and guides the positioning of the tip at distal end200. Representative systems for providing flexible tip endoscopes aredescribed in U.S. Pat. No. 4,802,461, and are widely used for surgicalprocedures.

The vaporization of uterine tissue using oxyhemoglobin as the primarychromophore is related to the incident power density, or irradiance,which can be expressed in Watts/cm². The overall rate of uterine tissuevaporization is a function of the spot size, absorption depth, and thepower density. A large spot with high power density, and rapidabsorption is ideal to rapidly vaporize tissue. A high power lightsource is required to achieve a large spot, high power density treatmentbeam. Peak laser power, average laser power, beam quality, deliverydevice design and delivery device placement all affect the efficiency ofvaporization. A treatment beam 28.5 Kw/cm² average irradiance with a85.5 Kw/cm² peak irradiance macro-pulse, with a spot size between about0.2 and 0.5 mm², rapidly vaporizes tissue.

FIGS. 8 and 9 illustrate the different optical penetration depths of the532 nm wavelength and 1064 nm wavelength used in prior art procedures.See, S. L. Jacques. Laser-tissue interaction. Photochemical,photothermal, and photomechanical. Surg. Clin N. Am. 1992; 72(3):531-558. The optical penetration depth of the 1064 wavelength beam fromNd:YAG laser beam is about 10 mm, which is 13 times larger than thepenetration depth of the second harmonic 532 wavelength laser beam,which is about 0.8 mm. As a result, the 1064 laser power is spread outover a much larger tissue volume than the power of the KTP laser. Incase of the 1064 laser as shown in FIG. 9, the temperature at the tissuesurface barely reaches 100° C. Therefore, only a small portion of tissuegets vaporized. But a huge volume of tissue gets coagulated (see spacebetween 100° C. and 60° C. isotherm).

The 532 laser beam, in contrast, is substantially completely absorbedwithin less than about 1 mm of the surface of uterine tissue. The laserpower is confined to a very small tissue volume. The high volumetricpower density results in a fast heating of the tissue and efficienttissue vaporization. Volumetric power density delivered to tissue is afunction of the absorbtion depth, irradiance in Watts/cm² and spot sizeon the surface of the tissue. The coagulation zone is very thin becauseof the small optical penetration depth of the 532 wavelength, andbecause substantially all of the radiation is converted to vaporizationrather than residual heat.

Other wavelengths which are substantially completely absorbed withinless than about 1 mm of the surface of the uterine tissue includewavelengths between about 200 and 1000 nm, including wavelengths lessthan about 700 nm, for example between about 200 nm and 650 nm.

FIGS. 10 and 11 illustrate a profile of a beam delivered to tissue usingone representative side firing optical fiber, to show spot size as afunction of distance from the side of the optical fiber. FIG. 10 is anend view, showing a fiber 600, cladding 601 on the fiber, an air space602, and a tip 603 through which the beam is directed by a reflectingface on the fiber. The cross-section of the beam is represented by thecrossing lines 604 and 605. As shown, the beam has a width in thisdimension of about 0.35 mm at 1 mm from the side of the tip 603. Atabout 2 mm from the side of the tip 603, the width is about 1 mm. Atabout 3 mm distance from the side of the tip 603, the beam width isabout 2.2 mm.

FIG. 11 is a side view, with like components given the same referencenumbers. The beam width in this dimension is represented by lines 606and 607. As shown, the beam has a width in this dimension of about 0.7mm at 1 mm from the side of the tip 603. At about 2 mm from the side ofthe tip 603, the width is about 1 mm. At about 3 mm distance from theside of the tip 603, the beam width is about 1.5 mm.

Thus, the spot size at 1 mm from the side of the tip is definedbasically by an ellipse having a major axis of 0.7 mm, and a minor axisof 0.35 mm. The area of the spot at 1 mm is around 0.2 mm². At 2 mm fromthe side, the area of the spot is about 0.8 mm².

For rapid procedures, according to the present invention, the spot sizeshould be large enough that the operator can remove tissue at areasonable rate, and see the results of a single pass of the spot over aregion of tissue. If the spot size is too small, the rate of theoperation is too slow. Also, if the spot size is too big, then theprocedure is difficult to control precisely. A preferred spot size isless than about 1 mm², and more particularly between about 0.8 mm² andabout 0.05 mm². Other apparatus may be used for delivery of the beamwith the desired spot size, including embodiments without divergingbeams, and embodiments with converging beams.

The irradiance of the beam at 1 mm from the side of the tip for an 80 Waverage power laser as described above is about 30 kiloWatts/cm².According to the present invention, it is desirable to provide awavelength between about 650 and 200 nm, with a spot size on the surfaceof the tissue less than about 0.8 mm², and preferably greater than about0.05 mm², with an irradiance greater than about 10 kiloWatts/cm², andmore preferably greater than 20 kiloWatts/cm², and even more preferably30 kiloWatts/cm² or higher.

FIG. 12 shows, heuristically, how vaporization rate and coagulation ratedepend on the volumetric power density. The vaporization rate (in mm/s)is defined as tissue depth that is vaporized per time interval. Thecoagulation rate (in mm/s) is defined as the depth of residualcoagulated tissue that remains after a certain time of vaporization.

Below a certain volumetric power density, referred to as a “vaporizationthreshold” in FIG. 12, no tissue gets vaporized. All laser energy staysinside the tissue. Tissue coagulation occurs where the tissuetemperature rises above approximately 60° C. As the volumetric powerdensity is increased a bigger and bigger tissue volume gets coagulated.

At the vaporization threshold, vaporization starts. Above thevaporization threshold the vaporization rate can be considered toincrease linearly with the volumetric power density for the purpose ofunderstanding the present invention, and as described by a steady statemodel for continuous wave laser tissue ablation, known by those familiarwith the art of laser-tissue interaction.

As more and more laser energy is consumed by vaporization of the tissue,the amount of laser energy leading to residual tissue coagulation getssmaller, i.e. the amount of residual coagulation drops. Thus, extent ofthe zone of thermal damage characterized by tissue coagulation leftafter the procedure gets smaller with increasing volumetric powerdensity, while the rate of vaporization increases. Substantial andsurprising improvement in results is achieved.

Publications about visual laser ablation of the prostate (VLAP) that isperformed with an Nd:YAG laser at 1064 nm have shown that this type oflaser is not able to vaporize a significant amount of tissue. Histologystudies have shown that the 1064 nm laser induces deep coagulation inthe tissue that results in edema and delayed tissue sloughing. Thiseffect was described by Kuntzman, et al., High-power potassium titanylphosphate laser vaporization prostatectomy. Mayo Clin Proc 1998: 73:798-801. Thus, in the heuristic diagram of FIG. 12, the VLAP procedureis believed to lie around point 650, barely above the vaporizationthreshold. Also, prior art technologies using 532 nm with spot sizes onthe order of 1 mm² with average output power of 60 Watts, are believedto lie, heuristically, around point 651 in the FIG. 12. Kuntzman et alpresent results for the coagulation depth of a 60 W continuous wave 532nm laser, with suggested operation at a distance of 2 mm from the sideof the tip, yielding less than 5 kiloWatts/cm² irradiance.

As the laser power is further increased to 80 W, and the side firingprobe is placed less than 1 mm from the tissue for a small spot size,the ablation rate further increases and the coagulation rate furtherdrops, so that the procedure lies heuristically at point 652 in FIG. 12.

A 80 Watt KTP laser can be used to easily reach irradiance levels thatvaporize substantially more tissue than is left as residual coagulationafter the procedure. More precisely, the vaporization rate issubstantially higher than the coagulation rate as given by thedefinition above, using high irradiance levels that are easily achievedwith higher power lasers. Because of higher vascularization in theuterus, the optical penetration depth is lower than in prostatic tissue,and therefore the volumetric power density at the vaporization thresholdcan be easily reached with lower average power lasers, including forexample a 40 W average output power laser.

FIG. 13 illustrates a uterus, generally 500, having myomas treatableaccording to the present invention, including intracavitery protrudingmyomas 501, 502, intracavitery pedunculated myoma 503, and intramural,submucosal myoma 540. Myoma 502 is located in the right cornu.Hysteroscope 505 is positioned through the cervix 506 with a flexibletip 507 adjacent myoma 502, and delivering laser radiation as describedabove.

FIG. 14 illustrates use of a side firing probe 509 for treatment of amyoma 510 located in one of the uterine cornua. FIG. 15 illustrates useof an end firing probe 511, for treatment of a myoma 512 located in oneof the uterine cornua.

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art, that various changes in form and details maybe made therein without departing from the spirit and scope of theinvention, as defined by the appended claims.

1. An apparatus for photoselective vaporization of tissue of a femalereproductive organ, comprising: a laser producing laser radiation; ahysteroscope, including an optical fiber coupled to the laser, adaptedto direct laser radiation from the fiber, and a flow of irrigant to atreatment area on a surface of the tissue; said optical fiber beingadapted to deliver the laser radiation at a wavelength and irradiance inthe treatment area sufficient to cause vaporization of a substantiallygreater volume of tissue than a volume of residual coagulated tissuecaused by the laser radiation.
 2. The apparatus of claim 1, wherein thelaser comprises a Neodymium doped solid state laser medium, and opticsproducing a second or higher harmonic output with greater than 40 Wattsaverage output power.
 3. The apparatus of claim 1, wherein the lasercomprises a Neodymium doped solid state laser medium, and opticsproducing a second or higher harmonic output with greater than 60 Wattsaverage output power.
 4. The apparatus of claim 1, wherein the laser andoptical fiber are adapted to deliver laser radiation having a wavelengthin a range of about 200 nm to about 700 nm, and has an averageirradiance in the treatment area greater than 10 kiloWatts/cm² and theoptical fiber is adapted to cause a spot size of at least about 0.05 mm²in the treatment area.
 5. The apparatus of claim 1, wherein the laserand optical fiber are adapted to deliver laser radiation having awavelength in a range of about 200 nm to about 700 nm, and has anaverage irradiance in the treatment area greater than 20 kiloWatts/cm²and the optical fiber is adapted to cause a spot size of at least about0.05 mm² in the treatment area.
 6. The apparatus of claim 1, wherein thelaser and optical fiber are adapted to deliver laser radiation having awavelength in a range of about 200 m to about 700 nm, and has an averageirradiance in the treatment area greater than 30 kiloWatts/cm² and theoptical fiber is adapted to cause a spot size of at least about 0.05 mm²in the treatment area.
 7. The apparatus of claim 1, wherein the laserand optical fiber are adapted to deliver laser radiation having awavelength in a range of about 200 nm to about 700 nm, and has anaverage irradiance in the treatment area greater than 10 kiloWatts/cm²,and the optical fiber is adapted to cause a spot size is less than about0.8 mm² in the treatment area.
 8. The apparatus of claim 1, wherein thelaser and optical fiber are adapted to deliver average irradiance of atleast 30 kiloWatts/cm² in the treatment area.
 9. The apparatus of claim1, wherein the optical fiber includes a side firing tip, and is furtheradapted for placement of said side firing tip within about 1 mm, orless, of the treatment area.
 10. The apparatus of claim 1, wherein theoptical fiber includes an end firing tip, and is further adapted forplacement of said end firing tip within about 1 mm, or less, of thetreatment area.
 11. The apparatus of claim 1, wherein the laser includesa Q-switch to produce micro-pulses during application of input power tothe laser medium, and a power source applying input power to the lasermedium in a sequence of pulses to generate macro-pulses of outputradiation, and wherein said output power is greater than about 200 Wattsduring said macro-pulses.
 12. The apparatus of claim 1, wherein thelaser includes a Q-switch to produce micro-pulses during application ofinput power to the laser medium, and a power source applying input powerto the laser medium a sequence of pulses to generate macro-pulses ofoutput radiation, and said irradiance is greater than 50 kiloWatts/cm²during the macro-pulse.
 13. The method of claim 1, wherein the laserradiation has a beam quality (M²) that is less than or equal to
 100. 14.The apparatus of claim 1, including a control system coupled to thelaser, and controlling output of the laser so that the laser radiationhas characteristics suitable to cause a treatment of uterine tissue, andsaid treatment is for a gynecological condition selected from leiomyomauteri, rhabdomyoma, endometriosis, endometrial hyperplasia, endometrialcysts, endometrial polyps, menorrhagia, uterine septa, intrauterineadhesions, or cervical intraepithelial neoplasia.
 15. An apparatus forphotoselective vaporization of tissue of a female reproductive organ,comprising: a laser producing laser radiation having a wavelength in arange from about 200 nm to about 700 nm; an endoscope, including anoptical fiber coupled to the laser, adapted to direct laser radiationfrom the fiber, and a flow of irrigant to a treatment area on a surfaceof the tissue; the laser and optical fiber being adapted to deliver thelaser radiation with an average irradiance in the treatment area greaterthan 10 kiloWatts/cm² and the optical fiber is adapted to cause a spotsize of at least about 0.05 mm² in the treatment area.
 16. The apparatusof claim 15, wherein the laser comprises a Neodymium doped solid statelaser medium, and optics producing a second or higher harmonic outputwith greater than 40 Watts average output power.
 17. The apparatus ofclaim 15, wherein the laser comprises a Neodymium doped solid statelaser medium, and optics producing a second or higher harmonic outputwith greater than 60 Watts average output power.
 18. The apparatus ofclaim 15, wherein the laser and optical fiber are adapted to deliverlaser radiation having an average irradiance in the treatment areagreater than 20 kiloWatts/cm².
 19. The apparatus of claim 15, whereinthe laser and optical fiber are adapted to deliver laser radiationhaving an average irradiance in the treatment area greater than 30kiloWatts/cm².
 20. The apparatus of claim 15, wherein the laser andoptical fiber are adapted to deliver laser radiation having a spot sizeis less than about 0.8 mm² in the treatment area.
 21. The apparatus ofclaim 15, wherein the optical fiber includes a side firing tip, and isfurther adapted for placement of said side firing tip within about 1 mm,or less, of the treatment area.
 22. The apparatus of claim 15, whereinthe optical fiber includes an end firing tip, and is further adapted forplacement of said end firing tip within about 1 mm, or less, of thetreatment area.
 23. The apparatus of claim 15, wherein the laserincludes a Q-switch to produce micro-pulses during application of inputpower to the laser medium, and a power source applying input power tothe laser medium in a sequence of pulses to generate macro-pulses ofoutput radiation, and wherein said output power is greater than about200 Watts during said macro-pulses.
 24. The apparatus of claim 15,wherein the laser includes a Q-switch to produce micro-pulses duringapplication of input power to the laser medium, and a power sourceapplying input power to the laser medium a sequence of pulses togenerate macro-pulses of output radiation, and said irradiance isgreater than 50 kiloWatts/cm² during the macro-pulse.
 25. The apparatusof claim 15, wherein the laser radiation has a beam quality (M²) that isless than or equal to
 100. 26. The apparatus of claim 15, including acontrol system coupled to the laser, and controlling output of the laserso that the laser radiation has characteristics suitable to cause atreatment of uterine tissue, and said treatment is for a gynecologicalcondition selected from leiomyoma uteri, rhabdomyoma, endometriosis,endometrial hyperplasia, endometrial cysts, endometrial polyps,menorrhagia, uterine septa, intrauterine adhesions, or cervicalintraepithelial neoplasia.